Due to the expansion of a large base of NMR users at the Scripps Research Institute, there is a greatly increased demand for NMR spectrometer. The drain on the NMR resources is exacerbated by the deterioration of the existing instrumentation, particularly at low field (500 MHz). This proposal outlines the need for a replacement console for an existing 500 MHz instrument, and an accompanying cryo-probe for the utmost available sensitivity. Together, the console and cryo-probe package will convert an obsolete AMX-500 MHz instrument into a state-of-the-art instrument and provide new technical capabilities. Although modern consoles are present at 600, 750, 800, and soon 900 MHz, it is critical to have access to a current generation instrument at 500 MHz as well. This is particularly important for field-dependent dynamics studies, and for studies of large systems where chemical shift anisotropy dominates relaxation, for example for phosphorus or aromatic carbons. Interpretation of 15N relaxation data required at low field (500 MHz) is more straightforward since the influence of potential site-dependent variability in the chemical shift anisotropy is small. In addition, the extraordinary sensitivity of the cryo- probe attachment will facilitate the study of samples with inherently low solubility or aggregation problems, and facilitate rapid folding experiments where sensitivity is critical.